The present invention relates to methods of making recirculating ball nut and screw assemblies which are internally preloaded to reduce lash. Preloading of the load bearing components or balls of ball nut and screw actuators is common in the production of ball nut and screw assemblies to achieve quality results without the necessity to hold undue tolerances, and to provide the consistency which is necessary to the use of the assemblies, particularly, for example, those which may be used on machine tools which perform close tolerance machining.
One method of fabricating preloaded ball nut and screw assemblies is disclosed in the present assignee's U.S. Pat. No. 4,643,041, issued Feb. 17, 1987, and involves utilizing a hardenable preloading plastic ring between a pair of nut members which exerts a preload once the ring, which is an epoxy ring, hardens.
Other patents, and I refer particularly to U.S. Pat. No. 3,479,897 granted Nov. 25, 1969, utilize springs, such as torsion springs, between two nuts which are provided in tandem relation on ball screws, and particularly, rolled screws which provide less precision than ground screws. Such preloaded ball screw and nut assemblies maintain the preload control necessary during the useful life of the system, despite wear, to achieve increased operating life.